Such hydropneumatic piston/cylinder arrangements are known; see, for example, Japanese Patent Publication 2006070950A. Such piston/cylinder arrangements may be used for various applications, for example, in vehicles, in particular in commercial vehicles, for the axle suspension, or in general technology as vibration dampers or shock absorbers or the like. A compact design of the piston/cylinder arrangement is essential for many applications, in particular for mobile use, e.g., as a spring leg. Known approaches, such as that disclosed in DE 35 12 232 A1, are not suitable for all applications. This application describes a hydropneumatic axle suspension for vehicles, i.e., for mobile use, but preferably for truck-mounted and mobile cranes, i.e., for heavy vehicles. The chassis of those vehicles is supported by hydraulic cylinders on their axles that are suspended on the frame. The hydraulic cylinders here are connected by hydraulic lines and cutoff valves to hydraulic gas or spring mechanisms arranged externally outside of the respective hydraulic cylinder and are connected to inlet and outlet lines for the hydraulic fluid by way of filling and drain valves. Due to the external gas or spring mechanisms plus the respective control system, the required installation space is accordingly high, and the response of the suspension is subject to a hysteresis and a time lag because of the long control distances via the aforementioned valves plus the inlet and outlet lines.
The known approach according to Japanese Publication 1006070950A, as cited in the introduction, overcomes these disadvantages by integrating the pneumatic spring mechanism in the cylinder in the form of a bladder mechanism. This approach is disadvantageous inasmuch as operational reliability is not ensured in long-term operation because the permeability of the material of the diaphragm of the bladder accumulator results in loss of gas from the bladder accumulator via diffusion. The measures described in the Japanese document to prevent gas diffusion by coating the diaphragm with an amorphous carbon layer are complex and do not offer absolute protection against gas diffusion through the membrane.